Overhead door



Dec. 15, 1936. J HEJCKMAN 2,064,470

' OVERHEAD noon Filed Jan. 1 7, 1931 i4 Sheets-Sheet 1 digs J J. A.HECKMAN Dec '15, 1936.

ovEfiunAn DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 2 I 4. (CH/gs.

J. A. HECKMAN OVERHEAD noon Dec. 15, 1936.

Filed Jan. 17, 1931 14 Sheets-Sheet 3 alga J. K HECKMAN Dec. 15, 1936.

OVERHEAD DOOR l4 Sheets-She'et 4 Filed Jan. 17, 1931 Dec. 15, 1936. J.A. HECKMAN OVERHEAD DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 5 Ill" IllDeb. 15, 1936. HECKMAN I I 2,064,470

OVERHEAD DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 6 Dec; 15, 1936. J A.HECKMAN 2,064,470

OVERHEAD noon- Filed Jan. 17, 1931 14 Sheets-Sheet 7 Dec. 15, 1936.

J. A. HECKMAN OVERHEAD DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 8- Dec..15, 1936.

J. A. HECKMAN OVERHEAD DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 9 Dec.15, 1936. J A. HECKMAN OVERHEAD DOOR Filed Jan. 17, 1931 Dec. 15, 1936.J. A. HECKMAN OVERHEAD DOOR Filed Jan. 17, 1931 14 Sheets-Sheet 11 Dec.15, 1936.

J. A. HECKMAN OVERHEAD DOOR Filed Jan. 1'7, 1931 14 Sheets-Sheet 12 Dec;15, 1936. 1 1A. HECKMAN 2,064,470

OVERHEIAD noon Filed Jan. 17, 1931 14 Sheets-Sheet 13 W,,,,,,,,,,,,,,, v297 v e Dec. 15,1936. J[ A. HECKMAN ,0

OVERHEAD DOOR Filed Jan. 17, 19:51 14 Sheets-Sheet 14 Patented Dec. 15,1936' UNITED STATE OVERHEAD noon John A. Heckman, Lincoln, Nebn,assignor, by

direct and Wilcox Manufacturing Company, a corporation of IllinoisApplication January 17, 1931, Serial 26 Claims. (Cl. 20-20) The presentinvention relates to overhead doors of the general type adapted to bemoved from a-substantially vertical closed position to an approximatelyhorizontal open position adjacent to or above the top of the doorway.Doors of this type have particular application to garages and in thefollowing disclosures of preferred embodiments of my invention I haveshown constructions particularly designed for garages, although it willbe understood that the invention is not limited to thisspecific type ofclosure.

These doors generally comprise a series of horizontally disposed,hingedly connected panels having rollers at their side edges whichtravel in tracks at the sides of the doorway. Said tracks comprisesubstantially vertical portions for holdmg the door in its closedposition, and substantially horizontal or inwardly extending portionsfor supporting the door in its open or overhead position. The verticaland horizontal portions of the tracks are joined by curved portionsofmove from the vertical portions to the horizontal portions in travelingbetween open and closed v positions of the door.

lems encountered in the average garage installa-- tion is that ofoverhead clearance between the level of the top of the doorway and theroof of -the garage or the structural supports for the roof,

' space is required to accommodate the overhead portions of the tracks,the counterbalancing means, and the movement of the door between openand closed positions. 1

One of the objects of the'invention is to pro- 'vide improved means forcounterbalancing the arrangement of counterbalancing means which thecounterbalancing forces efiective at counterbalancing means which iscarried by the door structure. In one representative form of myinvention 7 I prises a novel relationof spring means and cable sheavesdisposed above the doorwayin a compact of vertical-space above thedoorway, meansand cable sheaves cooperatingto equalize thecounterbalancing forces efiective at opposite 4 tion thecounterbalancing means the door structure, such arrangement completelyobviating the n essity for any space above or be-. low the horizontaltrack po ons or atany other .suilicient radius to enable the panels toeasily" improved, means One of the principal probwardly towards itsstantially vertical portions is necessary to design" these door and,more specifically, to provide a spring v i closure without opposing fopposite edges of the door, and also to provide the counterbalancingmeans com- I arrangement which only requires a small amount I the springedges of the door. Inanother form of my invenis carried by .7

: ing the. door in mesne assignments, to Richards- Aurora, 111.,

the door. As Lhave previously remarked in a 5' 1 large proportion orperhaps the majority of garage installations the overhead clearanceabove the top of the'doorway is quite limited; 'accord ingly, it isnecessary in these installations to have the horizontal portions of thetracks disposed-at a level closeto the top of the doorway or perhapseven below the top; In such cases, the curved portions of the tracksmust start their rearward curvature at a point below the'top of thedoorway and this introduces a problem in causing the top of the upperpanel to move into closed posi tion against the upperportions of thejambs and against the top of the doorway. My invention embodies improvedmeans whicheffectively closes the top panel against the doorway andwhich does not require any additional yertical clearance. Another objectof the invention is to provide for obtaining a weathertight the sides.of the door and the the door is being moved downclosed position orupwardly towards its open position itsitravel in the sub- 7 of thetracks should be unhindered by any app eciable frictional engagementwith the-jambs or other portions of the doorway, otherwise it will bedifficult to open and close the door and the action of thecounterbalancing means will be irregular. However, when the door is inits closedposition a substantially weather-tight joint should beestablished between. 5 the sides of the door and the doorway to excludesnow, .rain. and cold, and to. prevent rattling of the door by the wind,My invention provides improved means for effecting this weathertighttional resistance to towards or.

closure between doorway. When the travel of the door when'movin'g awayfrom its closed position. 1 H

Another obj v t of the invention is to provide an improved constructionand arrangement of Y electric motor driven operating mechanism for thisgeneral type of door; and to provide improved control means fortheelectric motor. Other objectsof myinvention are to provide improvedsafety means for instantly arresting the descent of the d rif one oithecounterbalancing cables. shouldbreak or it the counterbalauc- -ing meansshould'otherwise be rendered ineflfee tive; -'to provid 7 improvedlocking means for lock-.-

improved construction ot guide roller; and to 5 its closed position; toprovide an a a door being broken otherwise improve upon the hardware andlittings for this general type of door, as will hereinafter appear fromthe following description. While the present disclosures of my inventionhave been devised primarily for garage installations, nevertheless itwill be understood that certain fundamental principles of my inventioncan be embodied in pier doors and other types of closures where theclosure more or less vertically between its open and closed positions.

In the accompanying drawings illustrating preferred embodiments of myinvention:

Figure 1 is an elevational my improved door in its closed position, asviewed from the inner side of the doorway;

Figure 2 is a vertical sectional view through the doorway;

Figure 3 is an inner elevational view, partly in section, of oneembodiment of my invention showing the oounterbalancing means disposedabove the doorway, intermediate portions of the away to reduce theheight of the illustration;

Figure 4 is a side view, partly in section, of one of the swiveledsheave blocks forming part of the counterbalancing mechanism;

Figure 5 is an blocks;

Figure 6 is an inner fragmentary view of a modified construction inwhich the same general type of counterbalancing mechanism is mounteddirectly on the door;

Figure 7 is a fragmentary side view of the latter construction;

Figures 8-16 are difierent views of a modified construction wherein thecounterbalanoing mechanism is also mounted directly on the door, Figure8 being a fragmentary side elevational view of this modified embodimenFigure 9 is a fragmentary inner view, partly in section, of this latterembodiment;

Figure 10 is also a fragmentary inner view on a larger scale, showing inlongitudinal section ancing mechanism;

Flgure 11 is a verticalsectional view taken on the plane of the lineH'-l| end view of one of these sheave Figure 12 is a side elevationalview of one of the winding drums, viewed in the direction of the arrowsl2-l2 of Figure 13,

in section, to a view Figure Figure 14 is a side elevational viewof the'with the latter embodiment-of; counterbalancing sure is a sid vi w.Dq'fliatic, showing a diif t arrangementof the cables for the lattertype of counterbalancing m chanism; Figure 18 is a similar vlewfshowingthe use of pinions and racks for the latter type or coun- 4 m chanisminstead of winding drums and cablu;

member is movedviews, respectively,

view of one form of Figure 19 is ahorizontal sectional view through oneof the'guide tracks equipped with a rack, for use with the constructionillustrated in Figure 18;

Figures 20 and 21 are detail perspective views showing the juncturebetween the main overhead portions of the guide tracks and thedeflecting track portions for controlling the top panel;

Figures 22 and 23 are plan and side elevational of a modified form oftop panel controlling mechanism;

Figure 24 is a fragmentary side elevational view of a portion of thedoor and adjacent guide track structure, showing another modified formof top panel controlling mechanism;

Figure 25 is a horizontal sectional view through one edge of the doorshowing one form of sealing means for effecting a weather-tight jointbetween the door and doorway;

Figure 26 is a fragmentary side elevational View of one of the shiftablejamb members used in the type of sealing means illustrated in Figure 25;

Figure 27 is a bottom end view of shiftable jamb members;

.Figure 28 is a fragmentary side elevational view of an installationemploying a modified one of the construction of sealing means whereinthe lower track ment;

Figure 29 is a longitudinal sectional view through the lower portion ofone of these shiftable track sections, illustrating one form ofmechanism for positively'lift'ing -the,track section and for holding itin lifted position; v

Figure 30 is afront elevational view of the latter construction;

Figure 31 is 'a transverse portions are mounted for shiftingmovesectional view taken approximately on the plane of the line iii-3|of Figure 29;

different method of obtaining a weather-tight joint between the door anddoorway, this 'view corresponding substantially to a section taken onthe plane of the line 32-32 of Figure 33;

Figure 33 is a view, partly. in section, looking upwardly along the lineof the guide track illustrated in Figure 32;

Figure 34 is a side elevational view, on a larger scale, of the upperportion of a modified construction, wherein the top edge of the upperpanel is also moved to closed position by the shiftable track sections;

Figures 35 and 36 are detail views illustrating an adjustable keeperwhich can be associated with the locking mechanisms of any of thepreceding embodiments;

Figure 37 is a detail mechanism which may view' 6: a form of latch beemployed to hold the Figure 38 is a detail view of a simplified form oflocking mechanism for automatically descent of the door if thecableshould break;

Figure 39 is a perspective view of an improved 'door in open position;

construction of binge devised for these overhead doors;

Figure 40 is a longitudinal sectional view through this hinge, taken onthemedian plane Figure 41 is a longitudinal view of an improved type ofthese overhead doors, with theparts thereof shown in separated relation;

guide wheel or roller for ,Figure'42 is a similar sectional view showingthe wheel completely formed;

Figure 43 is an elevational view of the inner side of the present typeof door, provided with I motor driven operating mechanism;

Figure 44 is a side view thereof;

Figure 45 is an inner elevational view on a larger scale, partly insection, showing the driving relation between the electric motor and theshaft which carries the winding drums at the the spring reel or drum forwinding up the conductor cable leading to the electric motor on thedoor; 1

Figure 49 is a horizontal axial sectional view through this spring reel;and

Figure 50 is a circuit diagram of the electrical connections which maybe employed in this electrically operated type of door.

Referring first to Figures. 1 and 2, which show the main parts of atypical installation, the doorway 36 of the garage is defined betweenthe usual side jambs 31 and the upper lintel or cross bar 38. The frontwall 39 of the garage continues from the lintel 38 up to the roof, andthe walls or roof may be braced by any suitable arrangementi oflongitudinal or transverse cross braces 40 typical of ordinary garageconstruction.

The present door comprisesa series of horizontally extending panels orsections, there being. four of these panels 4|, 42, 43, and 44 shownalthough any greater or lesser number of panels may be used. The meetingedges of adjoining panels are hinged together by end hinges 45 andintermediate hinges 46. All of the panels may be solid, or the upperpanel may have window lights therein. Projecting from the sides of thepanels are guide rollers 41 which travel in the guide tracks at thesides of the doorway. There may be any desired number of these rollersfor the door, but in the preferred arrangement said rollers are providedat the bottom edge of the lower panel, and in proximity to the hingeaxes. of the several panels, and a pair of rollers 41a are mountedadjacent to the llpp r edge of the top panel 44 for controlling this toppanel. In such arrangement the intermediate pairs of guide rollers arepreferably mounted on the hinge pins of the outer hinges 45, as I shallpresently describe.

The guide tracks or rails in which these rollers travel are generallyindicated at and comprise the substantially vertical portions 52extending more or less parallel to the doorway 36 or jambs 31, thecurved'portions 53 which curve rearwardly back into the garage from theupper bracing beams 40 or other frame portion of the garage as by thehanger bracket 55 or the like.

In garage structures where the overhead clearance is comparatively smallby reason of the roof or ceiling being in close proximity to the topcross member 38 of the doorway, or by reason 'of the cross braces 40being comparatively low,

it is usually necessary to have the curved portions 53 of the tracksstart their rearward curvature below the top cross member 38 so as todispose the horizontal track portions 54 within the limited overheadclearance. In other garage structures where there is ample overheadclearance, enabling the horizontal track portions 54 to be disposed at ahigher level, the curved portions '53 .need not start their rearwardcurvature at a point below the top of the doorway. In the formerinstance where the overhead clearance is limited it is usually necessaryto provide a different arrangement of apparatus for causing the toppanel 44 to move into closed position against the cross rail 38 andupper portions of the jambs, as I shall hereinafter describe.

counterbalancing mechanism In Figures 3, 4, and 5 I have illustrated indetail one form of improved counterbalancing mechanism which is disposedabove the doorway and extends generally parallel thereto. Two flexiblemembers 58 in the form of cables or chains are.

fastened at their lower ends to the lower corners of the bottom panel 4|and extend upwardly to sheave blocks or guides 59 mounted above thedoorway. The guide rollers 41 and 41-11 are mounted on pins 51projecting from the side edges of the door, and the vertical stretchesof the cables 58 pass, from their lower points of attachment on the doorto the overhead sheave blocks 59, along the outer sides of the pins 51,that is, the cables are disposed between the outer sides of the pins 51and the outer side of the door. By so disposing the cables they may bearranged in planes between the side edges of the door and the guidetracks, which is the preferred relation, without interfering withthemovement of the guide rollers and pins back along the overheadportions of the tracks. It will be understood that, if desired, thevertical stretches of the cables may be disposed outside the planes ofthe guide tracks. Each cable passes inwardly over the. top of the sheaveglock 59 to a sheave block 6| around which it is reeved. Connectingstraps or clevis members 62 are mounted on the pivot axles 63 of the twosheaves GI, and extend towards each other for attachment to the oppositeends of spring means 64. This spring means may consist of a singletension spring, or where wider, heavier doors require morecounterbalancing energy, two or more. springs may be arranged inparallel. In Figure 1 I have shown three springs 64 in parallel relationwith their opposite ends secured to evener bars 62'. These evener barsmay be pivotally connected to the clevis members 62 for evenlydistributing the tension between the two or more springs, or these bars62, may be rigid with the clevis members 62. In Figure 3 I have showntwo tension springs 64 and 64', one within the other, there beingsufficient space between the springs so that the convolutions of onespring will not interfere with those of the other. The opposite ends ofboth springs are connected to the clevis members 62-62. The arrangementof one spring within the other is advantageous where it is desired thatthe entire counterbalancing mechanism have a minimum vertical dimension.The tension of the spring means 64 is so proportioned to the mechanicaladvantage of the sheave blocks 59 and 6| as to substantiallycounterbalancethe weight of the door in each of its different positionsin the 7 travel between open and closed positions.

looped around successive pulleys and fastened at one end to either ofthesheave blocks. Each sheave block 59 is preferably pivotally mountedfor swiveling on a horizontal axis. As shown in Figures 4 and 5, thepulleys 5911 are mounted between the arms of a yoke 66, the transverseportion of which is secured to or constitutes a part of a bracket member61. This bracket member has a hole therein through which a mounting bolt68 extends, said bolt being supported ina plate 69 constituting a partof the installed unit, or being secured to any other stationary memberabove the doorway. The bracket 61' is arranged to swing inwardly oroutwardly around the horizontal axis of the bolt 68, and to insurefreedom in this swinging movement ball bearings 1 I may be interposedbetween race grooves in the bracket 61 and race collars 12 mounted onthe bolt 68. The swiveled mounting of each sheave block 59 enables theblock to align itself with the line of pull acting down through thecable to the lower corner of the door. Referring to Figure 5, it will beseen that one of the pulley wheels 59ain this instance the outerwheel-is aligned vertically with the swiveling axis of the block. Thevertical stretch of the cable extending up from the door passes overthis outer-wheel and inwardly 'to the corresponding wheel of theinnersheave block 6|. Hence the pull onthis portion of the cable is alwaysaligned with the swiveling axis of the outer sheave block 59. Each yoke66 carries a downwardly disposed U-shaped fork orguide 13 be tween thesides of which the cable passes in running on the sheave block 59.Lateral deflection of the cable presses against one side or the other ofthe fork l3 and compels the sheave block 59 to swing correspondingly.Thus, as the door travels up to its overhead position and the lower edgeof the door swings inwardly to some extent along the curved portions 53of the tracks the sheaves 59 can swivel to align themselves with thisslightly diiterent angle of pull of the cables so that there is nopossibility of the cables running off the sheaves or binding thereon.Such also enables a latitude of positioning of the sheaves in theinstallation to be obtained since they can be located from the fact thatthe opposite ends of the same spring transmit lifting forces to theopposite sides of the door and hence the forces are always necessarilythe same so that there is never any tendency for thedoor to bind or dragbecause of unequalized counterbalancing. As the door travels up to itsoverhead position the diminishing tension of the spring; in proportionto the compounding of the cables around the sheaves 59 and 6|, is suchthat automatic compensation is made in direct proportion to thedecreasing portions 54.

V the sheave blocks or to the bracket weight of the door pullingdownwardly on the cables. Adjustments of the counterbalancing tensionmay be made at any desired point in the system, although I preferablyeffect these adjustments at the upper dead ends of the cablea the latterpreferably being connected to an extension arm 66a projecting from theyoke 66 01' each sheave block 59, any suitable adjustment being providedbetween the end of the cable and such arm. Obviously, an adjustment atone point is equalized between both sides of the door. For doors ofcomparatively wide span and considerable weight I may employ chainsinstead of cables, and effect adjustment by hooking different links atthe ends of the chains over hooks or pins on the extension arms 66a.

It will be observed that by extending the counterbalancing mechanismacross and directly above the doorway a. minimum overhead clearance isrequired and there are no difliculties in having the spring means andsheaves clearcross braces in the garage; also, there are no fixed pointsof anchorage required other than those for the bolts 68 directly at thesides of the curved track portions 53. This greatly simplifiesinstallation. In some installations it is possible to install thiscounter-balancing mechanism in the approximately triangular space 15(Figure 28) defined on the outer sides of the curved track portions 53between the. planes of the vertical and horizontal track portions, andin such installations no part of the entire assembly then extends abovethe plane assumed by the door when in its open'position on thehorizontal track Where more than one spring is desirable, the use of aspring within a spring, as shown in Figure 3, enables the verticaldimension of the counterbalancing mechanism to be reduced, where this isa factor in installation.

Figures 6 and 7 illustrate this same type of counter-balancing mechanismmounted on and moving with the door. In this arrangement, the cables 58are secured at their upper ends to brackets I6 or other fixed points ofattachment adjacent to the upper portions of the guide tracks and extenddown along the edgesor inner side of the door'to a similar compoundingarrangement of multiple sheaves 59 and GI which are mounted on the innerside of the door adja cent to the lower edge thereof. The multiple groupof outer sheaves 59 is mounted in a bracket 11 which is suitably securedto the door. An arm 18 extending from this bracket, or a separatebracket arm, supports a guide pulley 19 at a point spaced out from theside edge of the door so that the vertical stretch of the cable inpassing around'this pulley will be disposed outside the plane of theguide track at each side of the door. The pulley 19 is mounted forswiveling movement on a horizontal swiveling axis 8| which issubstantially aligned with the horizontal run of the cable passinginwardly to the multiple sheave blocks. Thus the pulley 19 can swivel toagree with the different angles of the vertfqalstr'etch of the cable asthe door moves between open and closed positions, without tending tocause the cabie to run off the multiple sheaves 596i.' The cableisreeved around successive wheels of these multiple sheaves insubstantially the manner described in the preceding embodiment, and isdead-ended to one of Th same'construction and arrangement is duplicatesat the opposite edge of the door. The spring means 64 connected to thetwo inner movable spring within a spring as shown in Figure 3.

This embodiment has the same equalizing action as the precedingembodiment, and it will be particularly noted that-by mounting thecounterbalancing mechanism on the door no overhead space whatever isnecessary for this mechanism. As above described, the vertical stretchesof the cables 58 are preferably disposed outside of the substantiallyvertical planes of the guide tracks 5| where they. will not interferewith the movement of the guide rollers 41 back along the overheadportions of the tracks, although, if desired, by locating the fixedpoints of attachment 16 for the upper ends of the cables below the upperportions of the tracks, or within the curved porabout an axis extendingsubstantially parallel' to the door. vBoth winding drums 85 are mountedon the end portions of a sleeve 86 extending beyond the side edges ofthe door. Collars 81 are mounted on the ends of the sleeve 86, beyondthe winding drums 85, and rotating on these collars are guide rollers41, an anti-friction ball bearing 88 being interposed between the sleeve81 and guide roller 41, if desired. The rollers 41 travel in the guidetracks, as previously described. The sleeve 86 is rotatably mounted in ahousing structure 89 carried by the door. Bearing support for the sleeveis afforded by two outer bearing blocks 9I and two intermediate bearingblocks 92, all secured to the housing structure 89 by set screws 93. Thesleeve may have plain bearings in these blocks, although I preferablydispose anti-friction roller bearings 94 in a recess in each block forrotatably supporting the sleeve 86. The counterbalancing tension isestablished by two coiled torsion springs 95 encircling opposite endportions of the sleeve 86 within the housing 89. The. inner end of eachspring is fixedly anchored to a notched out portion of each intermediatebear- ,mg block 92, as indicated at 96, and the outer end of each springis suitably secured to a collar trate each cable 58 as taking off itswinding.

drum at the inner side thereof, and in such arrangement the cablesextend up into curved supports I8I following the curved portions 53 ofthe tracks aroundthe inner sides thereof, the cables thence extendingrearwardly below the horizontal track portions 54 and being suitablyfixedly anchored at points adjacent to the rear ends of these horizontaltrack portions. Each curved support starts approximately at the lowerend -of' the curved track portion 53 and terminates adjacent to theupper end of said curved portion, serving merely to support the cable inan arc generally concentric to the curved portion of the track, althoughthese supporting members I8I may be extended further if desired. Asshown in Figure 9 they preferably consist of plates secured to the outersides of the guide tracks and having inwardly extending flange portionsI82 having upwardly turned lips at their inner extremities to form atrough for supporting the cable. The flanges I82 are spaced sufficientlyinwardly from the curved, track portions 53 to permit the winding drums85 to travel along the outer curved surfaces of said flanges. It will beseen that.such arrangement disposes each cable parallel to the vertical,curved, and horizontal portions of each track in inwardly'and downwardlyspaced relation thereto. In .this embodiment of my invention the axis ofthe winding drums 85 maybe disposed at any elevated point along theheight of the door because the, horizontal stretch of each cable can beextended back to any desired point under the overhead portions of theguide tracks. Manifestly, such embodiment requires no overhead clearancewhatever for the counterbalancing mechanism. In Figure 17, I haveillustrated another form in which the cable 58 takes off the front sideof each winding drum 85 and has its upper end anchored at I85substantially directly above the vertical portion of the track. Eachwinding drum may be disposed between the edge of the door and theadjacent guide tracks (in the general relation shown in Figure 10) with.the upward stretch of the cable disposed on the outer sides of theroller pins 51 where the cable will not interfere with the movement ofthe roll- -ers back along the overhead portion of the tracks; or thewinding drums 85 may be spaced outwardly in planes beyond the planes ofthe guide tracks. When having the cables take off the front sides of thewinding sheaves 85 it is to sheaves or drums-rotating about an axisextending parallel with the door I may combine automatic and manuallyactuated locking mechanism with the rotating member 86 on which thesheaves or drums are mounted. Referring to Figures 10, 11, 12, 13, etc.,it will be seen that two duplicate shafts I81 are arranged for endwisereciprocation in the bore of the sleeve 86. The ends of these shafts orrods are adapted to be projected outwardly beyond the ends of the sleeve86 for effecting locking engagement with the opposite tracks 5|. To thisend, the outer web portions of both vertical track sections are providedwith holes I88 adapted to receive the projected ends of the lockingshafts, one of these holes beingfprovided in each track at a point toreceive the associated shaft when-the door is in its completely closedposition, and further holes being provided at successively higher pointsfor 40 desirable that the axis of these sheaves be disreceiving theshafts for automatially arresting descent of the door in the event thatthe cable 6 or spring means should break, as I shall presently describe.The manual projection or retraction of the locking shafts or bolts I81from the lower holes I 88 is effected by the rotation of a lockinghandle I89 projecting from the front of the door. This handle is mountedon a shaft extending into the casing 89 and having sea cured theretooppositely facing cams III. III disposed between the front wall of thecasing and the sleeve 86, substantially as shown in Figure 11. When thehandle is rotated in one direction these cams exert spreading pressureagainst two collars H2, H2 for forcing them in outward directions alongthe sleeve 88.. These collars carry transverse pins H8 which extendinwardly through longitudinal slots 4 in the sleeve 88 and which passthrough or engage in the adjacent end of the companion locking bolt I01.Thus, the outward separating movement of the two collars II2 transmitsoutward projecting movement to the two locking bolts. Light compressionsprings II5 are confined between the collars I12 and the adjacentbearing blocks 82 for normally tending to shift the collars and thelocking bolts inwardly towards each other, so that when the manuallocking handle I08 is rotated in the other direction these springs willwithdraw the locking bolts from the lower holes I08 in the tracks.

Referring now to the automatic safety mechanism, each winding drum 85 ismounted so that it can have a limited amount of rotation relative to thesleeve 86, as determined by a pin II1 which is secured in the adjacentlocking bolt I01 and which extends out through a'longitudinal elongatedslot H8 in the sleeve 88 and engages in a triangularly shaped opening H8in the hub I2I of the winding drum 85 (see Figures 13 and 14) When thelocking bolt is retracted to releasing position the pin I I1 lies at theinner end of the slot H8 and at the inner narrow end of the triangularopening II8, and-when the locking bolt is projected outwardly to lockingposition this pin is at the opposite ends of both openings. One side ofthe triangular opening H8 is formed with an inclined cam surface 8'which, in the event of relative rotational movement towards the pin II1,functions to cam the pin in an outward direction for projecting the boltto its outward locking position. Referring to Figures 12 and 13, atanother point around on the hub I2I there is formed an arcuate slot I28from which projects a pin I24 to which one end of a tension spring I25is connected, the other end of this spring being anchored to the web ofthe winding drum. The inner end of the pin I24 is anchored to the sleeve88 and, if desired, a segment block I28, of shorter angular length thanthe slot I23, may be secured in the slot by the pin I24 passingtherethrough and being secured to the sleeve 88. This pin and segmentblock hold the'sheave 85 against shifting along the sleeve but permitthe sheave to rotate to a limited extent relatively to the sleeve. Inthe normal condition of the parts the counterbalancing tension of thesprings 85 tends to rotate the sleeve 88 in a clockwise direction asviewed in Figure 13 and this tension, preponderating over the tension ofthe spring I25, holds the pin I24 or segment I28 against the right handend of the slot I28, at which time the pin H1 is at the inner ends ofthe two openings H8 and H8. If either cable 58 should accidentally breakor become unfastened from its upper point of anchorage there is' noreaction pull tending to hold the sheave in such relation to the sleeve,

and hence the spring I 25 immediately snaps the sheave around in aclockwise direction (as viewed in Figure 13) with the result that thecam sur-' face I I8' revolves toward the pin Ill. This forces said pinoutwardly and projects the associated locking bolt I01 outwardly intoone of the holes I08 in the track so tiat the door is instantly lockedagainst descent. The tension of the spring" I25 tending to cam thelocking bolt in an outward direction is sufllcient to overcome theterclockwise direction relatively to the sheave (Figure 13) with theresult that the cam surface I I8 and the-pin I I1 have this samerelative movement for forcing the locking bolt outwardly into one of theholes I08 to lock the door against accidental descent. Thus, themechanism safeguards -the device against breaking or releasing of thecables or of the counterbalancing spring means, so that under nocircumstance can the door accidentally fall upon a person or car. Itwill be understood that both winding drums or sheaves have this same camand pinconnection with their associated locking bolts I01. Thecounterbalancing tension may be adjusted by rotating one of the drums 85in one direction or the other before the ends of the cables are fastenedthereto. To facilitate performing this operation, a series of aperturedbosses I28 (Figure 15) project inwardly from each winding drum, to oneside of the channel portion thereof, for receiving a tool inserted fromthe outer side of the drum and by which the necessary leverage can beexerted for rotating the drum before the cables are attached thereto.

This automatic safety locking mechanism may be incorporated inembodiments where the cables ta'te oil thefront sides of the drums 85,as shown in Figure 17. In such adaptations the relations of the springswould be reversed for the opposite direction of winding rotation of thedrums, and the locking holes I08 in the tracks would preferably beextended down to lower points because in those embodiments it isdesirable to dispose the winding drums adjacent to the lower edge of thedoor. 1

The automatic safety locking mechanism may be employed independently ofthe manually actuated locking handle I08, but where the latter is alsoincorporated in the structure it is advantageous to be able to disposethe mechanism 'housing 88 slightly higher on the door to facilitateestablishing an operative connection between the handle I08 and thelocking bolts I01 and to dispose .the handle in a convenient position.The present mechanism has this capability of being mounted at anydesired height on the door, and as illustrative thereof I have, inFigures 10 and 11, shown the mechanism built into the door approximatelyat the meeting line between the bottom panel H and the second panel 42.In this instance the housing 88 is of rectangular box-like form to formthe upper portion of the lower panel, and the line of hinge connectionsbetween the two panels is formed along the inner or rear wall of thishousing, this hinge axis being indicated at 45 in Figure 11. The hingescomprise a series of spaced lower plates I 8| (Figure 16) rigidlysecured to the lower panel H and a series of upper plates I82 rigidlysecured to'the second panel 42, these plates extending across the innerside of the spring housing 88 and having their meeting edges curled" toform the hinge eyes for receiving the hinge pins. Screws I84 passthrough the lower plates I8I directly below the hinge axis and threadinto the bearing blocks 8| and 82 for securing the plates I8I to thespring housing and bearing blocks. Holes I85 in the lower end plates

